Decks, Patios, Porches and Docks - Wood deck over concret patio

I have a covered concrete patio appx. 12 x 22 on the front of my house. All but the front edge and part of one side edge is totally covered and can't get wet unless we put water on it intentionally. We do have several plants that would be watered from time to time, but no major water should get on it. Here are Pictures (http://www.maverickwebdesign.com/html/porch_pictures.html) of the patio in question.

I have read several articles that talk about laying strips of wood (runners?) on the concrete first and then laying the main 2x6 lumber on top of that so I have something to screw the 2x6's into. What concerns me the most is water getting underneath the wood, whether from watering or from rain, especially on those edges that could get wet.

Is there any way to seal the slight cracks between the 2x6's where water won't get through? Is there a better way to keep this from happening?

We planned on putting a barrier of some kind down on the concrete before putting the runners down, but obviously water will set up on that too.

Any help is greatly appreciated.

jmmulkey,

Welcome to the forums.

First, water getting below the decking that you are talking about installing won't be an issue. You porch is (or should be!) sloped away from the house. Run your joists perpendicular to the front wall of the house and the deck boards parellel with it.

Sealing the joints between the deck boards would be a FATAL mistake. The boards need that gap to shrink and expand as they get wet and dry out, assuming that you are installing wood deck boards. If you will be installing a composite, they need that gap to shrink and expand as they get warm and cool.

There is no need for any kind of barrier on the concrete. Water won't hurt it. But that barrier WOULD trap water against the framing for the deck, and THAT will destroy the framing. DO NOT do a barrier!!

any wood in contact with concrete should be pressure treated, and should never come in contact with aluminum flashings or fasteners as they will fail. good luck!!

Check with your local Building Department. On another forum a woman had to put a railing up, on a deck built on a concrete slab. It was only 24" above grade, but her B.D. required guardrails 24" and up! The minimum code is 30". So you build, a neighbor reports it, you tear it down. Check first. Be safe, G